Metal-organic framework materials (MOFs) are a class of microporous and crystalline materials with great potential for adsorption-based separations. Harnessing the separation ability of these materials in high-performance liquid chromatography (HPLC) requires the use of small and uniform particles in order to achieve good column packing. The well-known MOF material [Cu-3(BTC)(2)] is, however, typically synthesized as a polydisperse mixture due to its nucleation and growth mechanism. It is demonstrated how a new synthesis method for (Cu-3(BTC)(2)] enables the formation of the MOF inside the pores of silica beads often used in chromatography, leading to monodisperse silica-MOF composite spheres with a uniform particle size of 3 mu m. When employed as an HPLC stationary phase, this material combines the good column packing properties of the silica and separation ability of the MOF material.